Transition Icon Properties

Transitions are lines that connect two states in a state diagram.

These lines have an arrow at one end signifying the direction of program flow through the transition.

Like a state, transitions have a display name (i.e. the text displayed on the state within the diagram) and an optional function (macro call, calculation, delay or execute C code) which is executed when the program flow traverses the transition.

In addition, transitions have a condition which is an expression that evaluates to true (non-zero) or false (zero).

The condition is used during program execution to determine if the program flow should proceed along that transition.

When a state has performed its own optional function, each transition leaving that state has its condition tested in turn to see which path the program flow should continue along.

Transitions have an optional label which can display the name of the transition, its condition, or its function.

Setting the colour of a transition sets the colour of its label.

The colour of the transition line and arrow cannot be altered.

The entry state icon includes a special transition leaving it which should point to the first state to be executed in the state diagram (after the entry state itself).

This transition is always connected to the enter state and cannot be deleted.

Also, it has no properties and so cannot have a label or code.

It is always executed as if its transition condition is true.

During program execution (simulation or ICD), the colour of the transition line changes to blue or orange when its condition is being evaluated – blue signifies the condition is false and the transition will be ignored, and orange signifies that the transition is true and the program flow with execute along this transition.

When the transition is executing, it changes to a thick orange line.